The subject is to provide liquid crystal display device having a short response time, a large voltage holding ratio, a low threshold voltage, a large contrast ratio, a long service life and a small flicker rate.

The liquid crystal display device having a liquid crystal alignment film formed on the opposing surfaces of a pair of substrates, and a liquid crystal composition therebetween, wherein the liquid crystal alignment film includes a polymer derived from a polyamic acid having a photodegradable group, and the liquid crystal composition includes at least one compound represented by formula (1) as a first component:

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R.sup.1 is alkyl having 1 to 12 carbons or the like; ring A is 1,4-cyclohexylene, 1,4-phenylene or the like; Z.sup.1 is a single bond or the like; X.sup.1 and X.sup.2 are hydrogen or fluorine; Y.sup.1 is fluorine or the like; and a is 1, 2, 3 or 4.

An object of the present invention is to provide a composition that has positive Δ∈, exhibits a liquid crystal phase over a wide temperature range, has low viscosity, excellent solubility at low temperatures, and high resistivity and voltage holding ratio, and is stable against heat and light. By using this composition, IPS or TN liquid crystal display devices and the like that have excellent display quality and suppress display failures such as image-sticking and drop marks are provided in high yield.

Provided is a composition that contains at least one selected from the group consisting of compounds represented by general formulae (i) and (ii) and at least one selected from compounds represented by general formula (iii). Moreover, a liquid crystal display device using the composition and an IPS or FFS device that uses the composition are provided.

The present invention relates to a liquid crystal display that incorporates a particular liquid crystal composition and a sealant in which a cured form of a particular curable resin composition is used. The present invention provides a liquid crystal display that prevents reduced voltage holding ratio (VHR) and increased ionic density (ID) in the liquid crystal layer and solves the problems of display defects such as voids, alignment irregularities, and image-sticking. Liquid crystal displays according to the present invention, featuring the ability to prevent reduced voltage holding ratio (VHR) in the liquid crystal layer and reduce the occurrence of display defects such as alignment irregularities and image-sticking, are useful particularly to liquid crystal displays in the IPS and FFS modes for active matrix drive and applicable to liquid crystal displays of equipment such as liquid crystal TVs, monitors, mobile phones, and smartphones.

The present invention provides a liquid crystal composition including at least one compound represented by General Formula (1), at least one compound represented by General Formula (2), and at least one compound represented by General Formula (LC1).

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The liquid crystal composition of the present invention has high refractive index anisotropy (Δn) and sufficiently low viscosity (η), achieves a wide nematic phase temperature range by suppressing a decrease in nematic phase-isotropic liquid phase transition temperature (T.sub.ni), and exhibits high compatibility. By using the liquid crystal composition of the present invention in a liquid crystal display element, a liquid crystal display element having a high response speed and high practical reliability can be obtained.

A liquid crystal display device that prevents a decrease in the voltage holding ratio (VHR) and an increase in the ion density (ID) in a liquid crystal layer and that resolves the problems of display defects, such as white streaks, variations in alignment, and image sticking. The liquid crystal display has features of preventing a decrease in the voltage holding ratio (VHR) and an increase in the ion density (ID) in a liquid crystal layer and suppressing display defects such as image sticking. Therefore, the liquid crystal display device is particularly useful for active matrix driving liquid crystal display devices with an IPS mode or an FFS mode and can be applied to liquid crystal display devices of, for example, liquid crystal televisions, monitors, cellular phones, and smart phones.

The present invention relates to a liquid crystal display device that includes a particular color filter containing a material containing chiral liquid crystals and a particular pigment. The present invention provides a liquid crystal display device that can prevent a decrease in the voltage holding ratio (VHR) of a liquid crystal layer and solve the problem of display defects, such as white spots, variations in alignment, and burn-in. Because liquid crystal display devices according to the present invention characteristically prevent a decrease in the voltage holding ratio (VHR) of a liquid crystal layer and reduces the occurrence of display defects, such as burn-in, the liquid crystal display devices are particularly useful as liquid crystal display devices in IPS mode and FFS mode for active-matrix driving and can be applied to household electrical appliances, automobiles, production facilities, measuring and analytical instruments, and communication devices.

Disclosed are a liquid crystal composition and a liquid crystal display device. The liquid crystal composition comprises at least one compound of general formula I, at least one compound of general formula II, at least one compound of general formula III, and at least one compound of general formula IV. By compounding the four compounds, the composition can have advantages of a wide temperature range of nematic phase, a low viscosity and a low threshold voltage, and the liquid crystal display element can have a short response time and great power saving performance.

A double layer liquid crystal device comprises a first and a second layer with orthogonal or crossed alignment of the liquid crystal phase of the two layers, in which the first and second layer have first and second alignment aids comprised of a polymerized or polymerizable molecular compound. The layers are aligned by UV photoalignment and vertical self-alignment by the aid of suitable additives.

The present invention relates to polymerisable compounds, to processes and intermediates for the preparation thereof, to liquid-crystal (LC) media comprising them, and to the use of the polymerisable compounds and LC media for optical, electro-optical and electronic purposes, in particular in LC displays, especially in LC displays of the polymer sustained alignment (PS, PSA) and self-aligning (SA) type.

LC media and LC displays containing an LC medium with positive dielectric anisotropy, which contains one or more compounds of formula I in a concentration of >0 and ≤10% ##STR00001##
and displays addressed by an active matrix and in particular displays of the IPS, PS-IPS, FFS, PS-FFS, HB-FFS, U-IPS, TN, PS-TN, STN or TN-TFT mode.